Foreign ministers from the American continent have urged Britain and Ecuador to peacefully end the standoff over the WikiLeaks founder, Julian Assange.

Assange, who is wanted in Sweden for questioning on sex allegations, has been granted political asylum by the South American country and has spent the last two months holed up in its London embassy.

The UK government has made it clear the Australian activist will be arrested and extradited if he steps outside the building after jumping bail.

Ecuador also claims that Britain has threatened to storm the embassy and detain 41-year-old Assange in a move that would violate diplomatic conventions.

The Organisation of American States (OAS) met in Washington on Friday to discuss the situation and passed a motion backing the "inviolability of diplomatic missions".

Senior officials from the 34-member bloc also urged the two sides to continue a dialogue to resolve the row.

The UK government has warned that it can legally enter the embassy and arrest Assange under the 1987 Diplomatic and Consular Premises Act, but the foreign secretary, William Hague, has said there is no intention of "storming" the building.

The paper, captured by Press Association photographer Lewis Whyld, was recorded at a briefing and appears to order officers to make the arrest if Assange attempts to leave in a diplomatic bag or vehicle.

A Scotland Yard spokesman said: "The document is one officer's notes from a briefing. Our objective is to arrest Julian Assange for breach of bail. Under no circumstances would any arrest be made which was in breach of diplomatic immunity."

Assange is refusing to travel to Scandinavia amid fears he will be extradited to the United States over his controversial website. Ecuador granted the Australian political asylum last week.

Ambassadors from several South American countries went to the embassy on Friday.

An embassy spokesman said: "This display of support for the Ecuadorian government by South American ambassadors is a clear indication of the level of support Ecuador has amongst countries in America and a clear statement opposing the UK government's threats against the integrity and sovereignty of its embassy in London."

Ecuador's president has said the diplomatic row "could be ended tomorrow" if Britain gave the activist safe passage to South America.

Rafael Correa said: "This could end tomorrow if the UK grants safe passage, or it could go on for months and years if Mr Assange can't leave the embassy of Ecuador in London."